KINGSTON — The state fire marshal’s office is investigating a suspicious fire that broke out at the Carriage Towne Plaza early Wednesday morning and forced several businesses to close, including the Post Office.

The cause of the fire remains under investigation, but Police Chief Donald Briggs Jr. said it appears someone entered the rear of the building before the fire began.

Seaman said firefighters discovered that someone had cut a hole in the wall leading from Asian Gourmet, which is vacant, to Carriage Towne Market.

Firefighters discovered the fire inside the market and knocked it down quickly, but not before the heat melted light fixtures and plastic.

“The fire did not extend beyond the market, but there is smoke throughout the entire building,” Seaman said.

Police and firefighters were alerted to the blaze when the fire alarms went off at the strip mall on Church Street.

Briggs said a police officer found flames coming from Carriage Towne Market.

Officers from Kingston and Brentwood gathered evidence at the scene that police believe will be “critical” to the case, Briggs said.

Briggs said police will assist the fire marshal’s office, which will notify federal agencies for possible assistance.

The building houses nine businesses — two of which are vacant — and the Post Office.

Yellow police tape was strung up around the front of the building and all of the businesses remained closed Wednesday morning.

They include medical offices for Core Physicians, which Briggs said planned to remain closed for the day.

“The fire marshal is going through each and every building to see if there’s any evidence of a crime or an attempted crime. Once the fire marshal goes through each and every building and makes that determination, at that point the buildings can be turned back over to the person in charge,” Briggs said.

Carriage Towne Market owner Devendra Patel arrived to see the damage for himself after he was notified by his alarm company. He’s owned the market for 15 years and said it is insured.